ABSTRACT
The new Lisbon metro line will cross a densely urbanized part of the city, connecting Rato station located at one of the hills of the city and Cais do Sodré station at the Tagus River right bank. Thus, the underground excavation intersects a wide range of materials, from rock mass to soft soils. The new Santos Station will be located partially beneath XIX century buildings with a cover depth of about 15 m, being these structures highly sensitive to differential settlements given its masonry and timber composition with multiple structural pathologies. Given the building conditions, its heterogeneous soil foundation and the level of surface settlements induced by NATM excavation, an underpinning solution was needed aiming to mitigate the buildings potential damages. Hence, high length micropiles, concrete reinforced beams and walls were executed from the building ground floor aiming to transfer buildings loads to the soils located underneath the tunnel excavation. This paper presents an overall description of the adopted solutions, how they were implemented and the buildings’ behaviour during the underground works.
